Year	Ratio
1971-01-01	0.381889998912811
1972-01-01	0.390940010547638
1973-01-01	0.418350011110306
1974-01-01	0.419450014829636
1975-01-01	0.424930006265640
1976-01-01	0.443470001220703
1977-01-01	0.426910012960434
1978-01-01	0.495429992675781
1979-01-01	0.493099987506866
1980-01-01	0.502170026302338
1981-01-01	0.511730015277863
1982-01-01	0.522459983825684
1983-01-01	0.510819971561432
1984-01-01	0.513040006160736
1985-01-01	0.521340012550354
1986-01-01	0.529980003833771
1987-01-01	0.525049984455109
1988-01-01	0.535589993000031
1989-01-01	0.528540015220642
1990-01-01	0.533429980278015
2000-01-01	0.679470002651215
2001-01-01	0.680010020732880
2002-01-01	0.680989980697632
2003-01-01	0.726549983024597
2004-01-01	0.732969999313354
2005-01-01	0.768830001354218
2006-01-01	0.791279971599579
2007-01-01	0.833150029182434
2008-01-01	0.842700004577637
2009-01-01	0.853699982166290
2010-01-01	0.851979970932007
2011-01-01	0.858009994029999
2012-01-01	0.869750022888184
2013-01-01	0.867709994316101
2014-01-01	0.851719975471497
2015-01-01	0.854499995708466
2016-01-01	0.852890014648438